NEW Brownells Lightweight AR-15 Bolt Carrier Group

Hrachya H
by Hrachya H
Brownells Lightweight AR-15 Bolt Carrier Group (1)

Brownells now makes lightweight AR-15 bolt carrier groups. While the bolt itself is a standard one, the bolt carrier has been lightened by cutting and machining out the material and leaving just enough to make it functional. As a result, the new BCG weighs 8.2 ounces.

Brownells Lightweight AR-15 Bolt Carrier Group (4)

The new Brownells lightweight bolt carrier is machined out of 8620 tool steel. The bolt is made of 9310 steel and is also magnetic particle inspected (MPI). The M16 notch is still retained on these bolt carriers in case if you have a lower receiver with a fun switch. The forward assist notches are also retained.

The black nitrided version of the Brownells lightweight BCG

This BCG is advertised to reduce the felt recoil. It may also be a useful part for lightweight AR builds. According to Brownells, the new BCG is compatible with 5.56x45mm NATO/.223 Remington, .300 Blackout and .204 Ruger calibers. I assume that it will work with many other cartridges with .378 rim diameter, too. However, because the manufacturer specifies only these calibers and because this is a non-standard part (despite being a drop-in one), it is probably a good idea to contact the manufacturer and make sure that the BCG is also compatible with the caliber you are going to use it with.

Brownells Lightweight AR-15 Bolt Carrier Group (2)
Nickel boron version of the Brownells BCG. The titanium nitride version is shown in the top image of this article.

The new Brownells lightweight bolt carrier group comes completely assembled. It has an O-ring in the extractor mechanism as well as properly torqued and staked gas key. These BCGs are available with black nitride, titanium nitride (TiN) or nickel boron finishes. They are already available for purchase on the Brownels website. Right now the MSRP of the black nitrided version is $119.99 and the BCGs with TiN and nickel boron finishes have an identical price tag of $139.99.

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Hrachya H
Hrachya H

Managing Editor Being a lifelong firearms enthusiast, Hrachya always enjoys studying the history and design of guns and ammunition. Should you need to contact him, feel free to shoot him a message at

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5 of 33 comments
  • FelterSnatch FelterSnatch on Feb 27, 2018

    They must have ripped off the design from Cryptic Coatings. I bought this exact same carrier over Black Friday (3 months ago).

    • See 2 previous
    • FelterSnatch FelterSnatch on Mar 01, 2018

      @Jesus Totally different coating though. Cryptic's is DLC coated. Will never go back to a Mag Phos or NiB carrier again.

  • Steve_7 Steve_7 on Feb 27, 2018

    It's pretty obvious most of the people commenting here haven't got a lightweight carrier. The carrier is the reciprocating part, so make it lighter and you have less recoil as there is less mass. Also it cycles faster, less mass. Comments about bolt bounce and so on don't really matter because it's not full auto, I suppose if you shoot really quickly you may encounter an issue but I've been using one in IPSC for ages and I've never had a problem. It wasn't that long ago that we were having gunsmiths shave down standard carriers. Makes sense to use a lighter buffer like the JP Enterprises buffer as well. I've never had any problems with the gas system either and even if I had I suspect it's a relatively easy fix. I should add you need to be using quality stuff, problems with crappy magazines and so on will become more acute as the gun cycles faster. Bolt heads break faster I think, JP makes a bolt head with better steel that lasts longer.

    The mass in the buffer and the carrier of the M16 and the M4 was put there for full-auto, never been quite sure why Colt's decided not to shave more weight off the carrier for the SP1 as it would save money, they came up with the semi-auto version pretty quickly so they probably never thought about it.